1. Field of the Invention
The present invention relates to a plasma display panel (PDP), and more particularly, to a PDP having high efficiency, high contrast ratio, and durability.
2. Discussion of the Background
U.S. Pat. Nos. 4,638,218 and 5,661,500 disclose a surface discharge PDP including a structure where sustain discharge occurs between two electrodes formed on a front substrate.
Discharge occurs between electrodes formed on the same substrate in a surface discharge PDP. Since the PDP's discharge sustain electrodes may be formed on the front substrate, a transparent material is formed on a light passing portion in a pixel region. Indium tin oxide (ITO) is a transparent conductive material that is widely used as a transparent electrode material. Since transparent material such as ITO typically has high resistance, it is partially used for a plasma discharge region, and the electrical signal transmission to the ITO electrode may be performed through metallic bus lines.
FIG. 1 is a schematic perspective view showing a typical structure of a surface discharge PDP, and FIG. 2 is a schematic cross-sectional view showing the discharge cell structure thereof. The upper substrate of FIG. 2 is shown rotated 90 degrees to help understand the discharge structure.
Referring to FIG. 1 and FIG. 2, a plurality of pairs of transparent discharge sustain electrodes 13a and 13b are arranged on an inner surface of a first substrate 10 in parallel with each other. Metallic bus electrodes (not shown) may be formed on the discharge sustain electrodes 13a and 13b. A dielectric layer 11 covers the discharge sustain electrodes 13a and 13b, and a protective layer 12, which may be made of MgO or the like, covers the dielectric layer 11. Additionally, a plurality of barrier ribs 21 having a predetermined height are formed parallel to each other on an inner surface of a second substrate 20, and they extend in the direction perpendicular to the discharge sustain electrodes 13a and 13b. Address electrodes 22 are arranged on a surface of the second substrate 20 and between the barrier ribs 21. A dielectric layer 23 covers the address electrodes 22. As shown in FIG. 2, a phosphor layer 24 is formed on side walls of the barrier ribs 21 and an upper surface of the dielectric layer 23.
In the surface discharge PDP, an initial discharge is induced by one sustain electrode and one address electrode, and the discharge is sustained by the sustain electrodes. Ultra-violet (UV) light generated in a discharge region is absorbed by the phosphor layer 24, thereby exciting the phosphor layer 24.
A shortcoming of the conventional PDP is that it typically has low discharge efficiency, which is caused by a short discharge distance and the planar electrode arrangement. Additionally, since the discharge is generated close to the front first substrate 10 of the PDP, ions generated therefrom may collide with, and damage, the protective layer 12, which shortens the PDP's lifetime. In addition, the phosphor layer 24 is formed on the rear second substrate 20 spaced apart from the discharge region, so that a relatively large amount of the UV light generated from the discharge region close to the first substrate 10 may not be absorbed by the phosphor layer 24.